O-(beta, beta, beta-trichlorotertiarybutyl) o-(2, 4, 5-trichlorophenyl) methanephosphonate



Patented Feb. 9, 1954 (can ammcnmnorrnarmnmurrm 0- (2,4.5- .-,.TRICHLOROPHENYL) METH- ANEPHOSBHONATE- Henry 'Tolkmith, 'Midland,

Mich assignor to The Dow Chemical Company, Midland, Mich a corporation of Delaware i No Drawing. Application April 21, 1953, a

Serial No. 350,227

1 Claim. (G1. 1 The present invention is.,directed .to' 045%,}?- trichlorotertiarybutyl) O (2,4,5 trichlorophenyl) methanephosphonate of the formula OH:P

in an inert organic solvent such as diethyl ether or benzene. The reaction is carried out in the presence of a hydrogen chloride acceptor, such as pyridine. Good results are obtained when substantially equimolecular proportions of the reactants are employed.

In carrying out the reaction, the 5,5,3-trichlorotertiarybutanol and pyridine are dispersed in the solvent and the resulting mixture added portionwise with stirring to the O-(2,4,5-trichlorophenyl) methanephosphonic chloride dispersed in the same solvent. The reaction mixture is thereafter heated for a period of time at a temperature of from 30 to 80 C. In practice it is sometimes convenient to operate at the boiling temperature of the reaction mixture and under reflux. Upon completion of the reaction, 4 the mixture may be filtered and the filtrate distilled under reduced pressure at gradually increasing temperatures to separate low boiling constituents and to obtain as a residue the desired 0-(5,5,5-trichlorotertiarybutyl) 042,4..5- trichlorophenyl) methanephosphonate. Since the desired product has a tendency to decompose at temperatures in excess of 150 C., distillation temperatures in excess of 150 C. for any appreciable period of time should not be employed.

The O-(2,4;5-trichlorophenyl) ,m'ethanephos 'jf phonic chloride employed. as a startingmaterial' 1 in the above described method may be prepared by reacting one molecular proportion of 2,4,5-trichlorophenol with at least one molecular proportion of methanephosphonic dichloride of the formula 0 CHr-i in an inert organic solvent such as benzene or diethyl ether. The reaction is carried out in the presence of a hydrogen chloride acceptor such as pyridine. In carrying out the reaction, the 2,4,5-trichlorophenol and the hydrogen chlo-- ride acceptor are dispersed in the solvent and the resulting mixture added portionwise with stirring to the methanephosphonic dichloride dispersed in the same solvent. The mixture is thereafter heated for a period of time at a temperature of from 35 to C. to complete the reaction. The reaction takes place smoothly at the temperature range of from 20 to 80 C. and at a rate which varies directly with the employed temperature. The reaction is somewhat exothermic, temperature being controlled by regulation of the rate of contacting the reactants as well as by the addition or subtraction of heat, it required. Upon completion of the reaction, the mixture may be filtered and the filtrate concentrated by distillation under reduced pressure to obtain as a residue the desired O-(2,4,5-trichlorophenyl) methanephosphonic chloride. Distillation temperatures substantially in excessof C. for any appreciable period of time should not be employed as the desired product has a tendency to decompose at such temperature. 0- (2,4,5 trichlorophenyl) methanephosphonic chloride is a viscous oil having a density of 1.5820 at 20 C. The latter compound and described method for its production constitute the subject matter of my copending application Serial No. 203,757.

In a representative preparation, 60 grams (0.338 mole) of [3,5,p-trichlorotertiarybutanol and 57.2 grams (0.723 mole) of pyridine were dispersed in 640 milliliters of diethyl ether and the resulting mixture added portionwise with stirring to 72 grams (0.245 mole) of O-(2,'l',5--trichlorophenyl) methanephosphonic chloride dispersed in milliliters of diethyl ether. The mixture was thereafter heated for 3 hours at the boiling temperature and under reflux to complete the reaction. At the end of this period, the reuct is effective as a parasiticide and adapted to '10 be employed for the control of a' wide range of agricultural and household pests such as flies,

mites, aphids, beetles, cockroaches and 'Southernr army worms. For such use, the compouminiayv be dispersed on an inert finely divided solid and 15 employed as a dust. Also, such mixtures may be dispersed in water with the aid of a dispersing i and wetting agent and the resulting aqueous suspensions employed as sprays.

In other pro- +3; cedures, the new product may be employed in go oils, as a constituent i0i1-,i n-water emulsions,,--

. or in water dispersion with or. without the addi, 1

tion oiemulsifying, wetting or dispersing agenta 4 Suitable concentrations of the toxicant in dusts are in the order of from about 0.1 to 10 percent by weight of the dust and in liquid suspensions from about 0.1 to 3 pounds per 100 gallons of the spray mixture ,In illustrative, operations, aqueous compositions containing the toxic methanephosphonate have been employed for the conv =trol ofrepresentative plant pests. In such operations, 100 percent kills of two-spotted spider mites,-. bean J'aphids and Mexican bean beetles have been obtained "at concentrations of 1.0, 0.5

and 0.5 pound, respectively, of toxicant per 100 gallons of spray mixturen This is a continuation in part of my copending application Serial No. v203,754, filed December 30, 1950. I claim: 04,8 8, 51 trichlorotertiarybutyl) O- (2,4,5 trichlorophenyl) methanephosphonate.

HENRY TOLKMITH.

No referenceswcited. 

